What should I use for partner API access control?

For partner API access control, the safest default is:

Use OAuth 2.0 with scoped access

This is usually the best fit when external partners need API access.

Why

• Delegated access: you can issue tokens with limited permissions
• Revocable: you can invalidate tokens without changing partner credentials everywhere
• Auditable: easier to track who accessed what
• Standardized: widely supported and easier to integrate

Recommended pattern

• OAuth 2.0 Client Credentials flow for server-to-server partner integrations
• Short-lived access tokens
• Scoped permissions per partner and per API/resource
• mTLS or private network controls if the API is highly sensitive
• API gateway enforcing:
  • authentication
  • authorization
  • rate limiting
  • request logging
  • IP allowlisting if appropriate

When to use API keys

API keys are okay for very low-risk use cases, but they’re weaker because they:

• often act like a static secret
• are harder to scope properly
• are harder to audit and rotate safely
• usually don’t provide strong identity assurance

If you use API keys, treat them as a bootstrap credential only, or combine them with:

• IP allowlists
• HMAC signing
• rotation policies
• per-partner quotas

Good security model

A strong setup for partners is:

1. Partner onboarding
   • unique client ID / secret or certificate
   • approved scopes
2. Token issuance
   • OAuth2 client credentials
3. Gateway enforcement
   • validate token
   • check scopes
   • rate limit
   • log requests
4. Operational controls
   • secret rotation
   • revocation
   • anomaly detection
   • partner-specific monitoring

Rule of thumb

• Server-to-server partner API: OAuth 2.0 Client Credentials + scopes
• High assurance / regulated: OAuth 2.0 + mTLS
• Simple, low-risk: API key only, but avoid if possible

If you want, I can also recommend an approach based on your exact scenario:

• internal partner vs external partner
• machine-to-machine vs user-delegated access
• public internet vs private connectivity
• regulated vs non-regulated data